With a declined approach at the loading dock the truck backs down a ramp until the back of the truck bed makes contact with the dock bumpers.
The truck bed is on a declining slope therefore the bottom of the trucks rear impact guard has pivoted forward and the bottom of the trucks rear impact guard is now further away from the face of the foundation wall than a truck that is backed into position at a level approach.
Vehicle restraints are typically installed on the face of the poured concrete foundation wall and are designed to capture a wide range of trucks rear impact guards. In a declined approach, pivoting the bottom of the trucks rear impact guard forward (as described above) cuts down on the “front to back” hooking range of the vehicle restraint.
For example if the declined approach has pivoted the bottom of the trucks rear impact guard forward 2” it is recommended to install a 2” thick vehicle restraint extension plate to maintain the vehicle restraints front to back hooking range. Failure to install the required extension plate could result in the restraint being unable to engage an increased number of trailers.
This link shows a vehicle restraint extension plate. https://www.pentalift.com/solutions/extension-mounting-plate-installation/
Another application that could require a vehicle restraint extension plate involves a projected pit. In some cases the projected pit does not extend completely down from the finished floor level to the exterior finished grade.
The partial height projected pit creates a gap under the dock leveler between the face of the projected pit and the face of the foundation wall. This link shows a partial height projected pit. https://www.pentalift.com/wp-content/uploads/2020/11/Projected-Pit-Dock-leveler-Benefits-1.pdf
If the pit is projected 4” it is recommended to install a custom height 4” extension to the foundation wall below the 4” projected pit to provide a flat even vertical surface on which to install the vehicle restraint.
For additional information on any Pentalift product please contact the Pentalift Sales Department.